The treatment of Army Pfc. Bradley Manning has been excessively harsh, as far as I can tell. If he is found guilty of leaking more than 700,000 classified documents, he deserves some punishment -- probably -- but should not be at risk of spending the rest of his life behind bars. Apparently.

I have to throw in all those qualifiers because Manning’s prosecution has been largely a secret process. Portions of his court-martial, which opened Monday at Fort Meade, Md., will be secret as well -- the important parts, presumably. The public may never know whether justice is properly done unless someone leaks the details of this trial about leaks.

But we do know that Manning has offered to plead guilty to a host of charges that could bring up to 20 years in prison. Rather than agree to what strikes me as more than adequate punishment, prosecutors insist on trying to convict him under the 1917 Espionage Act as, essentially, an enemy of the state. Which I don’t believe he is.

I say this even though Manning is allegedly responsible for the biggest unauthorized release of classified documents in the nation’s history. The material was disseminated by the website WikiLeaks, whose founder, Julian Assange, has taken asylum in the Ecuadorean Embassy in London. Assange fears that if he allows himself to be extradited to Sweden to face pending rape charges, U.S. authorities will eventually take him into custody -- and give him the same treatment they’re giving Manning.

After his arrest in May 2010, Manning has been held in isolation for months at a time and given such rough handling that the judge presiding over his trial, Army Col. Denise Lind, has granted him 112 days’ credit toward his eventual sentence if convicted.

I have struggled to sort out my own feelings about the Manning case. The only remotely comparable situation that comes to mind is that of Daniel Ellsberg and the Pentagon Papers. Ellsberg, too, was prosecuted under the Espionage Act; a federal judge dismissed the charges after learning of heavy-handed and illegal investigative tactics by the Nixon administration. Ellsberg is remembered as a whistleblower, not a criminal. For revealing what the government really thought about the Vietnam War -- as opposed to the lies it was telling the American people -- Ellsberg should be considered a hero.

And Ellsberg has been arguing that Manning should be seen in the same light. Manning said in pretrial proceedings that he wanted to “spark a domestic debate over the role of the military and our foreign policy in general.” Such a debate was already raging, but some of the material Manning allegedly leaked clearly told us things we had a right to know.

There was a video showing a helicopter raid in Baghdad in which bystanders, including journalists, were killed. There was evidence of unreported civilian deaths in Afghanistan. There were files indicating a lack of documentation for detainees sent to the prison at Guantanamo Bay.

Page 2 of 2 - But there was also a blizzard of diplomatic cables, some of which ended up being published without redaction of sensitive information such as the names of sources.

One difference between Ellsberg and Manning, I suppose, is that Ellsberg’s leak was more focused; the secret Pentagon study he slipped to The New York Times, The Washington Post and other papers amounted to 7,000 pages, as opposed to Manning’s alleged 700,000.

A more meaningful difference, perhaps, is that Ellsberg knew the material he was leaking showed the fundamental bankruptcy of U.S. policy in Vietnam, proving that officials did not believe their own rhetoric about “winning” the war. I doubt Manning understood a fraction of what he allegedly leaked.

Any such large, unsifted release of U.S. diplomatic cables is bound to include disclosures that put lives in danger. WikiLeaks and the news organizations that published some of the information tried to make appropriate redactions. Manning allegedly just threw it all out there, heedless of the consequences.

That kind of callous disregard, for life as well as the law, deserves punishment. But I believe “heedless” is the right word; it’s not at all clear that he wanted to give aid and comfort to al-Qaeda or the Taliban. Unless the government really believes he was a spy working for the enemy -- which I doubt -- he shouldn’t be prosecuted as one.

The government should make a plea deal. Twenty years is enough penalty to deter other potential leakers -- and enough time to begin crafting history’s verdict on Pfc. Bradley Manning.